COMPARATIVE RESULTS IN STEAM AND COAL CONSUMPTION 187 



DISCUSSION. 



Mr. E- H. B. Anderson, Member: — After the yacht had been in commission 

 a few months we were requested to make an inspection of the turbine machinery, 

 owing to the reason that the coal consumption was exceptionally heavy. 



This was done and some of the auxiliary machinery was foimd to be in need 

 of a thorough overhaul, and the astern turbine throttle valves were also in a leaky 

 condition. No internal examination of the turbines was made, but new propeller 

 wheels were fitted to the shafts. 



After these alterations were carried out two coal consumption tests were made, 

 each of 24 hours' duration, and on the second of which 33 tons were consumed. 



This would seem to be excessively high when compared with the builders' 

 guarantee, but it should be borne in mind that conditions out here are very different 

 to those which exist on a builder's trial carried out on the Firth of Clyde, and the 

 following reasons can be given for this statement. 



(a) The quality of coal obtained in New York cannot be compared with good 

 Welsh coal. 



(b) A coal test of 24 hours is much more severe than any 12-hour test, for one 

 reason, that it becomes necessary to clean all fires at least once, whereas on an 

 12-hour trial, starting with fine clean fires and burning Welsh coal, cleaning can 

 never be necessary. 



There is no question but that the coal consumption would have been reduced 

 by at least 12 per cent, with new propeller wheels, having machined driving faces 

 true to pitch and designed to meet a cruising speed of 13 knots. In addition, the 

 full speed of 15^ knots would have still been available. 



In connection with the coal tests, I wish to mention that every possible pre- 

 caution was taken to obtain accurate data and I feel confident that the recorded 

 figures are reliable. Regular 4-hour watches were the order of the day, with two 

 men on watch in the stokehold at all times. 



In connection with the combination arrangement, I consider Mr. Crane is to 

 be highly congratulated on the success he has achieved, and although I was unable 

 to be present on the final trials in July, 19 10, I was on board during a preliminary 

 trial in January, at which coal was measured for 36 hours and the data agree very 

 closely in each case. 



I now wish to draw your attention to the following: This economical result has 

 been obtained at a certain sacrifice, namely, speed, but of course with the conse- 

 quent increased cruising radius. I refer to Plate 61 which probably illustrates this 

 point in best manner. 



Curve No. 1. — Speed and revolutions of reciprocating engine only, with no 

 propeller wheels on wing shafts. 



